Lapatinib cancer drug, Computer model of a molecule of the cancer drug lapatinib. Atoms are represented as rods and are colour-coded: carbon (pink), hydrogen (white), oxygen (green) nitrogen (neon pink) fluorine (light blue) chlorine (dark blue) and sulphur (cyan). This drug, which is marketed as Tycerb, is used to treat solid tumours such as breast and lung cancer. It belongs to a class of drugs known as tyrosine kinase inhibitors. These drugs bind to tyrosine kinase growth factor receptors on the cancer cell's surface, inactivating them and so stopping cell growth and proliferation.